Blog

When to Plant Microgreens in Union County, GA

Union County, Georgia Zone 7b May

Your May gardening checklist

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 11
Avg. first frost October 23
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Fire up the seed-starting tray: microgreens

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Pick microgreens

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Instant PDF download. No spam, unsubscribe any time.

Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Union County, Georgia is in USDA Zone 7b. The average last spring frost is April 11 and the first fall frost is October 23, giving you a growing season of approximately 195 days.

At an elevation of 175 feet, Union County receives approximately 61.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, providing good warmth for Microgreens during the growing season. Clay soil retains moisture well for Microgreens, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Microgreens root diseases.

Union County, GA (Zone 7b) Moderate season
195 days
Last Spring Frost April 11
195 growing days
First Fall Frost October 23

Union County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (165 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Apr 7 – May 5
Recommended (50%) ✓ Fits season (160 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Apr 18 – May 16
Safe Start (90%) ✓ Fits season (165 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: May 10 – Jun 7

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Union County

How your county's soil matches Microgreens's growing requirements.

Soil pH

Your soil pH (5.8–6.2) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

The clay loam soil in Union County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

38
successive plantings in your 195-day season

Sow every 0.7 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Microgreens

Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Microgreens Needs Rainfall You Supplement Action
Jan 6" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 5.8" 0" ❄️ Dormant
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 5.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5.7" 0" ✅ Rainfall sufficient
Aug 4.3" 6.2" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.2" 0" ❄️ Dormant
Dec 5.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Microgreens Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Microgreens needs ~276 GDD — county provides 3,851 GDD Excellent fit

Microgreens Planting Timeline — Union County, GA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow March 28 Mar 28 – Apr 18
Harvest April 18 Apr 18 – May 16
Fall Sowing August 14 Aug 14 – Aug 28

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow Harvest
May Harvest
June
July
August Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

195 days in Union County

Growing Tips for Microgreens in Union County

Direct sow Microgreens outdoors after April 11 in Union County when soil has warmed and frost danger has passed.

With Union County's clay soil (28% clay), work in 3-4 inches of compost before planting Microgreens. Avoid tilling when soil is wet to prevent compaction.

Your generous 195.0-day season in Union County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Union County, GA?

Union County is in Zone 7b with an average last frost of April 11. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, GA?

Union County, Georgia is in USDA Hardiness Zone 7b. The average last spring frost is April 11 and first fall frost is October 23.

🌱

Your Union County Garden Planner — Free

A 24-page printable planner built for Union County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Union County, GA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.